The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK kinases. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. This cyclin tightly associates with CDK9 kinase, and was found to be a major subunit of the transcription elongation factor p-TEFb. The kinase complex containing this cyclin and the elongation factor can interact with, and act as a cofactor of human immunodeficiency virus type 1 (HIV-1) Tat protein, and was shown to be both necessary and sufficient for full activation of viral transcription. This cyclin and its kinase partner were also found to be involved in the phosphorylation and regulation of the carboxy-terminal domain (CTD) of the largest RNA polymerase II subunit.
^Wei P, Garber ME, Fang SM, Fischer WH, Jones KA (March 1998). "A novel CDK9-associated C-type cyclin interacts directly with HIV-1 Tat and mediates its high-affinity, loop-specific binding to TAR RNA". Cell92 (4): 451–62. doi:10.1016/S0092-8674(00)80939-3. PMID9491887.
^ abMichels, Annemieke A; Nguyen Van Trung, Fraldi Alessandro, Labas Valérie, Edwards Mia, Bonnet François, Lania Luigi, Bensaude Olivier (July 2003). "MAQ1 and 7SK RNA interact with CDK9/cyclin T complexes in a transcription-dependent manner". Mol. Cell. Biol. (United States) 23 (14): 4859–69. doi:10.1128/MCB.23.14.4859-4869.2003. ISSN0270-7306. PMC162212. PMID12832472.
^Kanazawa, Satoshi; Soucek Laura, Evan Gerard, Okamoto Takashi, Peterlin B Matija (August 2003). "c-Myc recruits P-TEFb for transcription, cellular proliferation and apoptosis". Oncogene (England) 22 (36): 5707–11. doi:10.1038/sj.onc.1206800. ISSN0950-9232. PMID12944920.
^Tian, Yanan; Ke Sui, Chen Min, Sheng Tao (November 2003). "Interactions between the aryl hydrocarbon receptor and P-TEFb. Sequential recruitment of transcription factors and differential phosphorylation of C-terminal domain of RNA polymerase II at cyp1a1 promoter". J. Biol. Chem. (United States) 278 (45): 44041–8. doi:10.1074/jbc.M306443200. ISSN0021-9258. PMID12917420.
^Kiernan, R E; Emiliani S, Nakayama K, Castro A, Labbé J C, Lorca T, Nakayama Ki K, Benkirane M (December 2001). "Interaction between cyclin T1 and SCF(SKP2) targets CDK9 for ubiquitination and degradation by the proteasome". Mol. Cell. Biol. (United States) 21 (23): 7956–70. doi:10.1128/MCB.21.23.7956-7970.2001. ISSN0270-7306. PMC99964. PMID11689688.
^De Falco, G; Bagella L, Claudio P P, De Luca A, Fu Y, Calabretta B, Sala A, Giordano A (January 2000). "Physical interaction between CDK9 and B-Myb results in suppression of B-Myb gene autoregulation". Oncogene (ENGLAND) 19 (3): 373–9. doi:10.1038/sj.onc.1203305. ISSN0950-9232. PMID10656684.
^Fu, T J; Peng J, Lee G, Price D H, Flores O (December 1999). "Cyclin K functions as a CDK9 regulatory subunit and participates in RNA polymerase II transcription". J. Biol. Chem. (UNITED STATES) 274 (49): 34527–30. doi:10.1074/jbc.274.49.34527. ISSN0021-9258. PMID10574912.
^Garber, M E; Mayall T P, Suess E M, Meisenhelder J, Thompson N E, Jones K A (September 2000). "CDK9 autophosphorylation regulates high-affinity binding of the human immunodeficiency virus type 1 tat-P-TEFb complex to TAR RNA". Mol. Cell. Biol. (UNITED STATES) 20 (18): 6958–69. doi:10.1128/MCB.20.18.6958-6969.2000. ISSN0270-7306. PMC88771. PMID10958691.
^Marcello, Alessandro; Ferrari Aldo, Pellegrini Vittorio, Pegoraro Gianluca, Lusic Marina, Beltram Fabio, Giacca Mauro (May. 2003). "Recruitment of human cyclin T1 to nuclear bodies through direct interaction with the PML protein". EMBO J. (England) 22 (9): 2156–66. doi:10.1093/emboj/cdg205. ISSN0261-4189. PMC156077. PMID12727882.